...What change should I expect to take place to my HERP/DERP after the next block?
If your hashrate and the pool hashrate is the same and you've been here for 5N, then your herp derp remains the same and you get the same payout each block if you're in the top 100. If not in the top 100, your herp remains the same and again your derp keeps rising till above the threshold and in the top 150 again.
Ahh, thanks for the detailed explanation.